Turning the car off at stop lights (questions about when, how long & wear issues)

[cfg83]

Lazarus -

Originally Posted by Lazarus

I agree. I can't remember the last time I had to replace a starter and I keep cars in the 150-200k range. Unless you're cranking it 30 seconds at a time to get it going I don't think that is much of an issue.

In the last year+ I have been reading up on hypermilers, the starter has not been a significant issue. I am guessing that the main candidates for failure are already faulty in some way.

CarloSW2

[NoCO2]

Thanks for the info. I have no problem replacing electric motor brushes so that's a non issue if nothing else gets worn excessively. I'm just concerned about the age of this car. It's only 12 years old and only has 55000 miles on it, but the engine was rebuilt after a terrible front end collision nearly totaled it so I'm just concerned about the condition of the parts to begin with. I guess I'll just do it and roll with the punches, keeping an eye on things occasionally to make sure I don't see any problems developing.

[Daox]

If I have to stop at a red light the engine is already off by the time I get there. However, if at all possible my engine is already off way before the red light and its green by the time I get near it. I then bump start and accelerate through the intersection, if I even need to accelerate.

[PaleMelanesian]

^ what he said, exactly.

Wayne over at Cleanmpg replaced his starter at about 90,000 miles. It's an automatic, so every restart had to be with the starter, no option to clutch bump-start it. And he has the engine off like CRAZY, too! I doubt it'd be a real problem for anyone else, either.

[s2man]

I used to think, like DifferentPointofView, that it took a long engine-off period to compensate for the energy used to restart the engine. So I only killed the engine at lights which I knew to be extremely long. But BMW has changed my mind. They are introducing automatic engine-off on their new models. The EU testing has a drive cycle which includes 12, 15-second stops on a 4.x miles course. All I can find now are articles stating this "reduces fuel consumption and emissions". But I remember reading one article which said they had an 8% reduction. Wow. That changed my thinking. I'm engine-offing a lot more now. And BMW only shuts off the engine once the car has stopped. Unlike some us who, as Daox said, shut off as we coast to the red light and save even more fuel.

[MetroMPG]

Originally Posted by PaleMelanesian

And he has the engine off like CRAZY, too! I doubt it'd be a real problem for anyone else, either.

Do you happen to remember if the reason for the starter failure was discovered? I had a look around & found references to the event, but no details on the ultimate cause.

I'd be curious to know what happened.

[NoCO2]

OK, so here is another question. I just refilled my tank yesterday and I thought I might compare my gas millage of the last tank (posted in garage) where I used only moderate driving conservation to obtain what I got. This tank I thought I might try turning off the engine whenever I idle for more then 30 seconds at a light. Well the first time I did it after the gas station, I tried to restart the engine and it sputtered to life, but then quickly stalled out. I tried again with the same result, so on the third try I revved the engine for a second after I started it and it worked fine. I think the problem is, is me starting it with my foot on the brake, however, I usually start the car cold with the brakes on and have no problem...what might cause this to happen? In my mind it makes no sense since I'm not doing anything different there from what I do starting it cold when I first get in, and I think that revving it up like that might out way the advantage of turning it off in the first place. Any advice?

[AndrewJ]

So when you were leaving the gas station, and you shut your car off: Was the car warmed up at that point? Or was the engine cold?

If I were you I'd go out and try to re-create the problem just to see what exactly the "trigger" for the problem is. If it's multiple cold starts, not starting well when warm, something like that.

[NoCO2]

The car was very much warmed up by the time I tried it. I make sure that the temperature gauge is at the position it is when warmed up before I attempt to do anything to improve fuel economy (coasting engine off, shutting down at lights) because I know starting with a cold engine is worse for fuel consumption and the engine in general.

The only thing I can think of is that I had a few things running that I usually don't when I start the car up. I always shut the radio off and lights off when I shut off after getting home or parking and when I was trying to do the starts last night I had my lights on and my radio on. It might be that the drain from the lights are too much for the battery to power and run the starter at the same time. Maybe I'll just turn the engine off during daylight hours if that can be confirmed and if it turns out that it works that way then I need to figure out how to power my lights and starter at the same time.

[DifferentPointofView]

that's really weird, whens the last time you had a new battery? it might be going out on you and not giving enough volts anymore to power those things and start it up. Otherwise it could be your alternator (if it's not disconnected like some modders do). Once started your alternator should power everything with ease, and help power the battery. It's not a standard tranny either, so I don't know why starting with the brakes would stall it unless you had a standard and it needed a slight go on the gas. Some vehicles require you to use your brake to shift or start the vehicle. Spark plugs and wires good? they could be going bad too. were you running on empty at the time? you could have had no fuel going into the engine at the time until you filled up and reved it.